In certain fuel delivery systems, such as a propane gas system, the consumers are supplied propane gas from a tank of liquefied propane. The tank is typically isolated from any established fuel pipelines, and therefore must be periodically refilled. A float level sensor is used in the propane tank to monitor the liquefied propane level. In such systems, the user periodically views the tank level sensor and then requests delivery of replacement propane as required. While such fuel level sensors which are mounted in the tank can provide a reliable indication of the liquefied propane level remaining in the tank, they are difficult to maintain and time-consuming to repair when needed in view of their placement within the tank itself.
It is therefore desired to provide a propane tank level monitoring system which can not only sense and display the level liquefied propane in the tank, but which can also provide a signal to a central location to use the information to track gas usage rate and to schedule delivery of replacement fuel as needed. In particular, it is desired to provide an in-line gas flow rate sensor for sensing the gas flow rate from which the level of the propane remaining in the tank can be derived.